N (p-aminophenyl) hexamethylenimines



Patented Sept. 30, 1952 N(P-AMINOPHENYL)HEXAMETHYL- ENIMINES Maynard S. Raasch, Wilmington, DeL, assignor to-E. I. du Pont de Nemours and Company,

: Wilmington, Del., a corporation of Delaware No Drawing. Application March 29, 1950, Serial No. 152,753

1 v This invention relates to a new class of organic amines. More particularly it relates to aromatic amines which j, contain a hexamethylenimine radical. Still more particularly it relates to N- (p -]aminophenyl)hexamethylenimines and to their preparation and to photographic developer compositions containing the same.

Paraphenylenediamine and its N-dialkyl derivatives having an unsubstituted -NH2 group are well-known commercial developing agents for the formation of silver images. and dye images. However, these compounds are often not highly soluble in theedeveloping solutions and also they are irritating to the skin of most persons. Moreover, in the color development process, the pphenylenediamines sometimes do not produce the desired color in'the final image. For these reasons, numerous derivatives of p-phenylenediamine have been. proposed in the technical literature, for example, in U. S. Patent 2,304,953

pounds with as""N-'(p-aminophenyl)-piperidine and N-(p aminophenyl)morpholine are very weak photographic developers.

Theneworganic compounds of thi invention are, generically, the hexamethylenimines having a p-aminophenyl group attached to iminonitrogen and their addition salts with acids, especially strong mineral-acids, e. g., hydrochloric, sulfuric,

phosphoric and sulphamic'.

The hexamethylenimine radical may have one or more hydrogen atoms in the 3, 4 and 6 position substituted by various monovalent radicals including alkyl, ether radicals, e. g., alkoxy, aryloxy, cycloalkoxy radicals, and secondary non- -aromatic amino groups R i fi 'm-w I\R' where E is-hydrocarbon;preferably of 1 to 12 carbon atoms or the Rs'together form with the 8 Claims. (0!. 260-239) 2 p nitrogen atom a cyclic radical or 5 to 6 carbon atoms), etc. g

An important class of the N-(p-a'minophenyl) hexamethylenimines have the general formula:

CHrCHrCHz where R is an ether radical, preferably of one to twelve carbon atoms, the oxygen atom of .which is attached to the fourth atom of the hexamethylenimine ring. This ether radicalmay' correspond to that of an aliphatic or cycloaliphatic monohydric alcohol or of an aromatically-substituted aliphatic monohydric alcohol or, of a mono ether of a glycol including a polyglycol. Thus Rmay be alkoxy, alkoxyalkoxy, alkenyloxy, aralkoxy, etc. Suitable specific radicals are metboxy, ethoxy, isobutoxy, tert.-butyloxy; n-o ctyloxy, .dodecyloxy, Z-ethylhexoxy, sec-butyloKY. ethoxyethoxy, methoxymethoxyethoxy, methoxyethoxy; allyloxy, crotonyloxy, cinnamyloxy; cyc1opentyl-- cxy, cyclohexyloxy, B-methylcyclohexyloxyg; geranyloxy; benzyloxy, phenylethoxy, etc. In the preferred compounds of this formula R is .an,al koxy radical of lto 3 carbon atoms. The compounds of Formula I can be prepared by reacting the i-ether substitutedhexamethylenimine with a p-nitrohalobenzene andreducing the. resulting N- (p-nitrophenyl) hexamethylenimine to convert the nitro group to an amino (NH2) group. g v

Alternatively, the hexamethylenimines maybe reacted under heat and pressure with brIomobenzene in the presence of copper powder .to produce the N-phenylhexamethylenimines,. which on nitrosation and reduction yield theN-(paminophenyl)hexamethylenimines.- l i i The -ether substitutel hexamethylenimines can be advantageously prepared in .thesame manner as unsubstituted hexamethylenimine by catalytic hydrogenation of the adiponitrile in the vapor phase, as described in U. S. Patent The ether-substituted adiponitriles can be obtained by addition of the appropriate alcohol or ether alcohol to 1,4-dicyano-Z-butene or lA-dicyano-l-butene as described :in U. S. application Ser. No. 20,830, filed by G. F. Hager on April 13, 1948, now U. S. Patent No. 2,500,9f12. The reaction can be carried out withja wide range of proportions of reactants but in general it is preferable to use an excess of the alcohol, e. g.,

-0.1 to 30 moles excess, in order to insure complete reaction of the dicyanobutene. It is preferably carried out by dissolving in the alcohol to be reacted catalytic amounts, e. g., 0.001 to 0.05 mole per mole of dicyanobutene of an alkali metal, e. g., lithium, sodium and potassium, and adding the 'dicyanobutene to this solution. The reactionls spontaneous and takes place readily at low temperatures; for'instanceyfrom -10 to +50" Another class of useful N-(p-aminophenyl) hexamethylenimines are those wherein the substituent radical is a non-aromatic:isecondam;

amino radical. A preferred class is:

CHPCEIEGE+F 4 cals of one to six carbon atoms, e. 3., methyl, ethyl, propyl, n-butyl, n-hexyl and the like. They may be prepared from the corresponding hexamethylenimines, which in turn are made by hydrogenating the alpha-alkacrylonitrile dimers such as methacrylonitrile dimer,

NCCHCH2CHzIC-CN H2 I Hz obtained .the processwdescribed, in U. S. 2,282,'785;;1 Moreover, activezhydrbgen compounds such as alcohols may be added to methacrylonitrile dimer and the product, upon hydrogenation,

' gives hexamethylenimine having a. methyl group omthiii' carbom. and. an alkoxymethyl group on the 6 carbon.

Griz-0H,- H, 11 I where R and R are monovalent non-aromatic 1 hydrocarbon radicals, preferably of one to twelve carbon.atoms or together form a single bivalent evens organic radical of five to six'carborr. atoms, and, are, ioined to. the. nitrogen atom through an aliphatic carbon atom. These compounds can be prepared in thesame manner as the 4-ether substituted compounds of F-ormularl by substituting the 4-amino -substitutedhexamethylemmine for ,the 4-ether. substituted compound in the reduction procedure described above. In the most p-refe'rredfcompbunds-of:thisioimula, R and -R. are

-hsjs me-anaers a'llty-l -groupsof 1; to 6 carbon atoms: 1

Birr'iilarly,'--the- 4=amino substituted hex-ameth- 91 mines-ca-nbe' prepared by catalytic hydroation' of the-appropriatebeta-aminoadiponiile 1af-ter; the-5 manner outlined above; and de- "scribed for hexamethylenimine-in U. s. Patent 200-282. The}beta-aminoadiponitriles can be sued (by adding" secondarygnon aromatic "-I-A-dioyano-2-butene or'lA-dicyano-lheasdejs'eribeddn application Ser. No. 28,522. e useful beta-aminoadiponitriles: which H eso -t'reatedare; beta-dimethylaminoadipo- "ni lie;'-beta-diethylaminoadiponitrile, beta-dial- Iyiaminoadiponitrile; -beta di-n-butylaminoaidipenitril'e; betadi n-octylaminoadiponitrile; betadi n dodecylaminpa'diponmile, "beta-distearyla' ,hoadiponitrile; beta-dioleylaminoadiponitrile,

fbeta piperidinoadiponitrile; s-morph o-linoadipo nitrile; beta -piperazinoadiponitrile, beta' dicyclohezgylarn inoadiponitrile; beta-thiomorpholinoadi'ponitr'ile, *beta pyrrolidinoadiponitrile, betahexamethyleniminoadiponitrile, betadi(.beta- "methoxyethylamino)'adiponitrile; beta N,N- methylhexamethylenediaminobis-adiponitrile,

and the like -R-and'yR' in Formula II, of course,

may cor'respond: tothe radicals in the beta-adipo- IfitifiGS just listed;

I Anotheruseful classbfcompounds-"are the "N- -(p-aminophenyl)hexamethylenimines where the "carbon atomsinthe 3 and fi' positions of the I hexwmethylenimineiringare-substituted by alkyl' :1- 1 I 1 v i I l (III) swherelii: R can,ci-l'tf areirr abhz 1 w: alky radia alysis:

Hexamethylenimines may also be made by recasing the corresponding caprolactams with lithiumsaluminumhydride, or in some cases by heating the corresponding hexamethylenediamine hydrochloride:

Photographic developer compositions can be Y The invention isfillustrfated' inIgreatende tail butlsnotintended'jtoiibe'limite'd'bythelolldwihg xamples. in h ch' artsia by we ht? M w A solution of 60:partsgoflahexamethylenimine and lparts-of, p.-nitrochlorcbenzene;in 200; parts ofon-butyl alcohol wasrheated atereflux (about 120. E.). ;for; 19..hours. The .solventwvas'removed under. .reduced-rr-pressurer eandrztherresiduea was washed with.water, dissolved: in. milpanhandlincentrated. hydrochloric acid, and thersolutionzwas filtered-.1 r'Ifhe,flltrateawas.diluted-with-water:and

made alkaline with. sodium-."hydroxide; a --Thespre.-

cipitatep'f cr..ude.N-.(p -nitrophenyl) --hexamethy1.- eniminei. which formedw-as,-rfiltered ofi, washed with water and dried... 'I?he'yield-was60.parts;,or 91%, .oi.the,.-theoretical.. Afteretwoirecrystaliizava -ver es vtions. from. methanol .athe .oproducte-meltedf-l at Calculated-for G1QH1GON2YNTI2L 7Wf, H p Found: j 'N;f 1' 2,'62;'1'1'2'.'8fi;

4 A; solution ofcl parts-ion Ni tpenitroplienyll hexamethyleniminez im'l4i0' parts of tlianol swas ohargedcwithzfi partsiof-i'Raney niclelu catalyst into: a bomb;- whilchsxwaseheaited at: 50 -6113 05101 1.5 hours under-a hydrogempres'sure ofi K300 21100 lbs/sq. in. to effect quantitative reduction. The resulting reaction miXturewas filtered to remove the catalyst and evaporated with excess hydrochloric acid to obtain the dihydrochloride of N-- (p amin phenyllihexamethyieniminei which a re stai ed mimethanor 7;;

. A solstice 9 -3; 1 P s. o -me h x n iethylenirri'ine nd 24 parts. or. a s benzene in 80 parts'of n-butyl alcohol genatedfas; in Example "I; After recrystallizaltralization equivalent'i128.3s(calculated: 129.2)

Analysisz Calculated for C1zH sN2'.2HC1:- G1,-26.9 FoundcCLZBQ mEmm e n trobromowas heated at reflux for 16 hours. The solvent was removed I under reduced pressure and the residue was washed with water, and recrystallized from ethanol to give 27 parts (72% yield) of N-(pnitrophenyl) i- 4 methoxyhexamethylenimine, M. P. Eli-55C. The nitro compound was hydro:

tion from alcohol, the dihydrochloride-of N-(p- A aminophenyl) 4 methoxyhexamethylenimine melteclat184 187C. p

galculated ,m o naomz" 11.2 Found: 01,243

The 4-methoxyhexamethylenimine of this ex- ..ample was prepared, by-hydrogenating betamethoxyadiponitrile in dio'xane, solution in the presence of areducedcobalt catalyst at 120-130" C. and 100-160 atmospheres pressure. It boils at 75-.75;6 C. at mm. pressure, 11 1.4673, neusw m I A solution of l9-partsof 4'-dimethylaminohexamethylenimine. and Y parts of p-nitrobromobenzene in 80 parts of n-butyl alcohol was heated at reflux for 16 hours. The solventwas removed 'under reduced pressure, thefresidue was dissolved in dilute hydrochloric acid and the solution was filtered. Upon adding sodium hydroxide to the filtrate, crude N-(p-nitrophenyl) 4-dimethylaminohexamethylenimine separated. This was purified by converting it to the sulfate, which after two recrystallizations from methanol was obtained as a light yellow solid melting at Analysis:

Calculated for (C14H21O2N2.)2.H2SO4: S, 5.13 Found: S, 5.07

The nitro compound was reduced by heating it with iron powder and water. When reduction was complete, as indicated by the disappearance of the yellow color of the nitro compound, sodium carbonate was added in amount equivalent to the sulfate ion present and the .resulting N-(p- Example IV A solution of 42 parts of 3,6-dimethylhexamethylenimine and 26 parts of p-nitrochlorobenzene in 120 parts of n-butyl alcohol was heated at reflux for hours. The solvent was recovered under reduced pressure and the residue was washed with water. There was obtained 33.5 parts (82% yield) of N-(p-nitrophenyl)-3,6-dimethylhexamethylenimine, P. 91-921, srecrystallizatioir from m ethan L 1 a I t, 'This*\ compound was v.-hydrogenate to the procedure. described inifixampleg L-iand the... Ns (p-aminophen ll-fifi-dimeth lhexam 'yleniminewas crystallized. as the dihydrochloride Qfrom ethyl alcohol. 1 When;;tested;iny :a waterethyl alcohol solution:containing sodium carbonate, N- (p-aminophenyl) .-3,6-dimethylhexameth ylenimine dihydrochloride showedgstrong' de- =velopingaction., v 1. 4 ,1, The 3,6-dimethylhexamethylenimine .of this example was obtained by hydrogenating the dimer ofmethacrylonitrile in .dioxane. solution, first with a palladium-on-carbon catalyst wat 25-40 C. to reduce the double bond. and7 -then with a Haney cobalt catalyst at 125 C. to reduce the nitrile groups. The, imine wasseparated from the reaction mixture by fractional distillation. It boiled at 169- 170.5.C.

. The N-(p -aminophenyl hexamethyleniminesof i Examples I, IIlan d III weretested ,ina'developer emi e ei e er th e i :25 (st m of 7 sodium carbonate, 10 grarnsof. sodium sulfite, 2

solution comprising 10.0125 -;mole; ;of,. the} N tpgrams of potassium bromide andwate'r vtoinake 1000 milliliters (in the case of the compound "of Example I, 350 milliliters ofalcohol were used as part of the developing compositionf to effect complete solution). Color film having as the silver M halide binder a polyvinyl acetal of a magenta color-forming aldehyde of the type describ'ediin U. S. Patent 2,397,864 was exposed,v developdin the above solutions and further processed in fixing and bleach baths in theusualinanner, Comparative dye densities at 540 millimidronsi were as follows:

Product of Example I 2.75

Product of Example II e- 2.79 Product of Example III 2.48

Under identical conditions, the closely related N-(p-aminophenyl) piperidine gave a dye density of only 0.3, paminodiethylaniline gave a dye density of 2.54. I

The N (p aminophenyl) hexamethylenimines are preferably handled in the form of their addition salts because of their greater solubility and. stability. The preferred salts are those formed with organic or inorganic non-oxidizing acids having a dissociation constant above 1 x 10*, e. g., acetic acid, benzoic acid, oxalic acid, chloracetic acid, phosphoric acid, hydrochloric acid, sulfuric acid, etc. The more useful salts are those formed with strong mineral acids.

The N (p aminophenyl)hexamethylenimines of this invention are among the strongest known color developers, exceeding in some instances the activity of p-aminodiethylaniline. When a. solubilizing group, e. g., dimethylamino, is present they are less apt to cause skin irritation than 13- aminodiethylaniline. They may be used in developing compositions containing color formers for color development of exposed silver halide contained either in the conventional gelatin or in a' synthetic polymer colloid binding agent, and

as rubber accelerators, antioxidants for gasoline,

1 5 where Q is 1. A compound taken from the-icms cd hsi fimg yl er nmmfsffna njgf gn genera "far:

d5 momdamar of 1 to a'ii tibbn \CHPCHJP H;

a secondary amino 

1. A COMPOUND TAKEN FROM THE CLASS CONSISTING OF AN N - (P - AMINOPHENYL) HEXAMETHYLENIMINE AND ITS ACID ADDITION SALTS.
 2. THE ADDITION SALTS OF THE N-(P-AMINOPHENYL)HEXAMETHYLENIMINES HAVING THE GENERAL FORMULA: 